Attempts to realize automatic travel of work vehicles that perform work-traveling have been conventionally made. In order to realize automatic travel of work vehicles, a work region in which work is to be performed has to be recognized through map data or the like. For example, in an unmanned working method for a cultivated land work vehicle disclosed in Patent Literature 1, first, outer perimeter teaching is performed in which the vehicle does one lap through manual driving along the outer perimeter of a piece of cultivated land that is a work region. Accordingly, map coordinates and reference travel cardinal-directions of the cultivated land are calculated. Next, a travel work route along which work-traveling is to be performed over the entire piece of cultivated land is set. Then, the cultivated land work vehicle automatically performs work-traveling along the travel work route based on positional information and travel cardinal-direction information of the vehicle in the cultivated land, which are obtained from moment to moment. Accordingly, work-traveling over the entire piece of cultivated land is automatically performed. The cultivated land work vehicle described in Patent Literature 1 is a tractor that performs tilling work, grading work, soil-puddling work and the like. The tractor performs work-traveling over the entire piece of cultivated land.
Patent Literature 2 discloses a method for calculating a target travel route of an automatic travel rice planting machine. The rice planting machine performs seedling planting work by repeating linear work-traveling. Furthermore, this rice planting machine includes a GPS for measuring the machine body position. Then, the position of a GPS antenna when a teaching switch is pressed at the start of teaching is taken as a start point, and the position of the GPS antenna when the teaching switch is pressed at the end of teaching is taken as an end point. A reference line connecting the start point and the end point is calculated based on information regarding the obtained start point and end point. Then, a straight line that is parallel to the reference line (line segment) and based on a planting width is generated as a target route for planting work-traveling.